Correction to: European Journal of Human Genetics (2010) 18, 163–170; doi:10.1038/ejhg.2009.152; published online 7 October 2009

Since the publication of the above paper, the authors noticed that the affiliation of Umberto Balottin and Fausta Piazza is incorrect. For both the co-authors the affiliation is Child and Neuropsychiatry Unit, University of Pavia, IRCCS Fondazione C. Mondino, Pavia, Italy.

The authors would like to apologise for this mistake.